Purfling-groove cutter



B. J. ROY.

PUR.FL|NG GROOVE CUTTER. APPLICATION FILED IIIAII, I0, 1921.

Lgfygw, Patented OCI. 24, v1922.

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nutren stares BENJAMIN J. ROY, 0F SEATTLE, WASHINGTON.

PURFLING-GROOVE CUTTER.

Application filed March 10, 1921. rSerial No. 451,166.

To all whom it may concer/n:

Be it known that I, BENJAMIN J. Bor, a citizen of the United States, and a resident ofthe city of Seattle, county of King, State 0f Washington, have invented certain new and useful Improvements in Purfling- Groove Cutters, of which the following is a Specification. v

My invention relates to purfling groove cutting machines,A more particularly it relates to improvements in the groove cutting Imember itself and in a guide along which the piece whereinthe groove is being formed,

`may be advanced to the cutter.

The principal object of the present inguide block or gauge having opposite sides adapted' to iit the coveX or concave curves vwhich the cutter is required to follow and which makes the work of guiding the piece easier, especiallyfor beginners using the machine..

Another object of the invention resides in the details of construction of the cutter, whereby it may be used informing grooves of various widths.

A still further object of the invention resides in the means provided for adjusting the guide block to different positions, and in the means `for retaining it at an adjusted position.-

In accomplishing these and other objects ofthe invention, I have provided the iin- -proved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein- -showing its use incutting al Figure 1 is a side elevation of a purfling groove cutting machine, embodied by the present inventionn i Figure 2 is a vertical section of the same, taken on the line 2 2 in Figure 1.

Figure 3 is a' plan view of the machine, groove in the back section of a violin body.

Figure 4 is an enlarged, detail, sectional view through the cutter shaft supporting bearing.

Figure 5 is a perspectivefview of the cute ter forming discs in disassembled relation.

Figure 6 is an enlarged, sectional view of vthe guide block supporting and locking device.

'Figure 7 is a plan view illustrating the disposition of the guide when a groove is being formed along a convex curve.

Figure 8 is a similar view showing the disposition of the guide when working along a C or concave curve. L

Referring more in detail to the several views of the drawingsl 1l designates a horizontal work support ing table which is mounted, at one side of its side of its center, upon a standard 2. that is slidably contained to move vertically within a tubular post 3 that is fixed rigidly upon a flat baseplate 4. A lever 5 is pivotallv mounted upon the upper end of the post L3 between two upstanding ears 6, with its inner end dsposed beneath the table in such manner that vertical movement of its outer end will cause the table to be adjusted vertically for a purpose presently disclosed.

Also mounted upon the base 4L is a standard 8 equipped, at its upper end, with suitable bearings as at 9, wherein a horizontal shaft 10 is revolubly contained. At its outer end, which is disposed above the adjacent edge of the table 1, the shaft is equipped with a circular cutter 11, which will presently be described in detail, and at its other Vend, has a belt wheel 12 fixed thereto which lines up with a belt wheel 13 on a drive shaft le that is revolubly carried within the lower end of the post 3. The latter shaft is equipped with a belt wheel 15 whereby it may` be driven, and a belt 16 is extended ,about wheels 12 and 13 to provide for driving iio wood is gouged out from between the cuts made by the end cutters. lt has been found by experimenting that the success of the cutter to a great extent is due to the irregularity of the teeth of the intermediate disks and for this reason ,they are not all made alike or arranged in any particular order when ssembled.

`Each cutter disk is provided central-ly with an aperture 2O for receiving a screw 2l which threads into the end of the shaft, or arbor l0, to hold the cutters tightly together and fixed to the driving shaft. Y Directly beneath the cutter, the table has a recess cut therein wherein a guide block 2G is located, and against which the edge of a piece of work, such as the back section of a violin as shown at 27 in Figure 3, imay be moved to gauge the 'distance zof the groove from the edge of the piece.

This guide block is mounted at the upper end of a stem 28 that is `sl'idably supported in the upper and lower `arms 29 and 30 of a bracket that is 'fixed to lthe standard 8, `itorma'lly the stem is retained at its upper limit by means of a spring `31 that is wound about the same and `bears against 4the arm 30 and against a cylindrical knob` Siixed on the stem. A

The guide block has a semi-circular, radially curved convex surface 35 which is turned against the piece of work when operating along the C curves or on concave surfaces, as yshown in Figure 8, and at its opposite side has a slightly concave surface 36 which lis turned against the work when the groove is being formed along convex surfaces, as illustrated in Figure 7. rlhe vertical movement of the stem which carries the guide permits the latter to beadjustedto use `either face without the work `havingto be removed from the cutter.

To hold the guide at anadjusted position, l have provided a `locking pin 40, Figure G, which is mounted in the standard 8. At its outer end the pin has a knob Lil thereon, and at its inner end has a point fil-2 adapted `to seat within the sockets formed in the Aknob A groove i5 is formed circumferen* tially half way about the knob 32 which leads into vertical grooves 46 and 47 at opposite sides of the knob, 'and inthe opposite ends of these latter ygrooves sockets i8 are formed for receiving the end of the locking pin.

The lpin is yieldingly Aheld against lthe knob by means of a spring t9 `that is seated within a socket formed inthe standard 8 about the pin, and bearslagainst a shoulder 5l on the pin. `This construction provides for locking the guide block at raised or Vlowered position with either face in position for'engaging the piece being grooved. i Assuming that the device is -so :constructed, in using the same, "the piece `fto 'be grooved is placed upon the table l and the table raised to bring the work against the cutter 1l the latter is then driven through the belt connections provided, to cause a groove to be cut within the piece parallel to itsedge as the piece is moved along the v'guide block. lhile the groove is being formed along the convex surfaces, as is shown in `Figure 3, the guide block is adjusted so that the face 36 thereof will 'engage the piece. But, when the groove is -bei-ng formed along the C curves, or concave1surfaces,the `guide .is reversed sothat the surface 35 will engage the work. This adjustment is -eii'ected by drawing-the pin i0 outwardly to release the knob 32, .so that the latter may vbe moved downwardly .and revolved to bring its opposite face "into vpo sition i r f it is desired to increase `the depth 4of the groove being formed, the outer Vend of the lever v5 is moved downwardly to raise the table. llf the groove lis to tbe made wider or narrower, 'the 'cutter is removed from 'the shaft vl() and more -or ffewer ofthe cutters 1-9 inserted, so that the desired width can be obtained.

The distance that the groove `is formed from the edge of the piece may be varied bythe adjustment `ofthe shaft 10 outwardly or inwardly; it being held at any position of adjustment fby Imeans of the lpulley wheel 'l2 which is secured thereto, in .any suitable manner. i

Having thus described my invention, what fl laim as new ftherein and desire to secure fby Letters Patent, is: j l

l. ln a imachine :of the class described, the combination with a work supporting table, and a :rotary cutter for -making grooves insaid work, of a reversible `guide block mounted adjacent fsaid cutter, against which said work may be advanced `and guided ito 'the cutter.; said 'block having `convex yand concave yguide :surfaces .at its oppofsite sides lforithe purpose set forth.

2. In a machine of the Vclassi-described, the combination with a work "supporting table, and a rotary vcutter Ifor makin lgrooves in said work, of a vrevolubly :ant lslidably mounted guide block supporting stem, a guide block fixed to said shaft :and

disposed adj aeent the cutterl against which vthe work imay lbe advanced .and `guided :to the cutter, said'blockihaving convex and concave guide surfaces :at i opposite sides thereof and a yieldable docking member for retainling the shaft and )block =at adjusted post tionsfor the use of veither guide surface.

3. In a machine of the cl'assedescribed, the combination with la work supporting table, and a rotary cutter for-making `grooves in said -work, of 'a revolubly and slidably mounted fguide block supporting estem, a guide block 'Xed fto `said-shaft`land Adisposed adjacent the Cutter against which. the Work may he advanced and guided to the cutter; said block having convex and eoncave guide surfaces at opposite sides thereof, a cylindrical knob iXed on said stem having sockets at diametrically opposite sides thereof, a yieldable -iocking pin having a pointed end adagted to be projected 

